Metal implant for generating soft tissue and attaching to an implant

ABSTRACT

One embodiment of the present invention is directed to compositions and methods for enhancing attachment of soft tissues to a metal prosthetic device. In one embodiment a construct is provided comprising a metal implant having a porous metal region, wherein said porous region exhibits a nano-textured surface.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/173,372 filed on Oct. 29, 2018, which is a continuation ofU.S. patent application Ser. No. 15/700,931 filed on Sep. 11, 2017,which is a continuation of U.S. patent application Ser. No. 15/236,828filed on Aug. 15, 2016 (now issued as U.S. Pat. No. 9,788,953), which isa continuation of U.S. patent application Ser. No. 14/528,339 filed onOct. 30, 2014, which is a continuation of U.S. patent application Ser.No. 13/764,259, filed on Feb. 11, 2013 (now issued as U.S. Pat. No.8,906,402), which is a divisional of U.S. patent application Ser. No.12/544,575, filed on Aug. 20, 2009 (now issued as U.S. Pat. No.8,399,008), which is a continuation of U.S. patent application Ser. No.11/020,587, filed on Dec. 22, 2004 (now issued as U.S. Pat. No.8,329,202), which claims priority to U.S. Provisional Application No.60/627,216, filed on Nov. 12, 2004. The entire disclosures of each ofthe prior applications are hereby incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to biomedical devices and methods ofattaching soft tissues to plastic and metallic prosthesis.

BACKGROUND OF THE INVENTION

Soft connective tissues (e.g. tendons, ligaments, joint capsules)associated with, or spanning, a diarthrodial joint contribute tostabilizing the joint and provide the means for effecting relativemotion between the bones. These soft connective tissues have a veryunique morphology in terms of their insertion site into bone [Rufai etal., J Orthop Res (1995), 13:585-593. Benjamin et al., J Anat (1992),180:327-332; Ralphs and Benjamin, J Anat (1994), 184:503-509; Frowen andBenjamin, J Anat (1995), 186:417-421]. As the soft tissue structureapproaches its insertion site into bone, the tissue morphology changesfrom a dense, regular, longitudinally aligned tissue tofibrocartilagenous tissue, to calcified fibrocartilagenous tissue, andfinally to bone tissue. Additionally, the collagen fiber orientationchanges rapidly from being longitudinal (i.e. along the soft tissueload-bearing direction) to being perpendicular to the calcificationtidemark. This uniquely differentiated transition one at the insertionsite is typically referred to as the “enthesis.” The normal biology ofthe soft tissue enthesis (a) ensures a gradual transition from a softtissue to a much stiffer bone tissue, (b) minimizes mechanical stressconcentrations at the attachment site, and (c) maximizes the tendonpullout force from the bone.

Total joint replacement procedures (primary or revision) frequentlyresult in the loss of the attachment site of these soft tissuestructures due to osteotomy or simply to gain access to the joint. Tofully restore joint function, these soft tissue structures have to bereattached at their anatomical (or equivalent) location around thejoint. Such reattachment, however, is a challenging task since itrequires mating of two very dissimilar materials i.e. a soft, biologicaltissue material and a much stiffer, non-biological (metallic or plastic)prosthesis.

One aspect of the present invention is directed to a composition andmethodology that recreates the soft tissue enthesis morphology, as foundin natural tendon, ligament, and capsular insertion sites, between themetallic implant and the soft tissue structure to be reattached to themetallic implant.

SUMMARY

A composite implant for attaching soft tissues to a plastic or metallicprosthesis and a method of preparing such composite implants comprisesone or more of the following features or combinations thereof.

One embodiment of the present invention is directed to a compositeimplant that upon implantation in vivo regenerates the variouslydifferentiated tissue zones at a tendon attachment site around adiarthrodial joint. This invention will enable soft tissue attachment toa metallic implant, or a metallic surface, by enabling the regenerationof tissues having incrementally increased stiffness including, forexample, layers selected from the group consisting of:tendon/ligament/capsular tissue, fibrocartilage tissue, calcifiedfibrocartilage tissue, bone tissue, metal implant. Hence, the implant ofthe present invention and the methodologies described herein create arobust connection with high pullout strength between the soft tissue andthe implant.

In one embodiment a composite implant is provided for enhancingattachment of a soft tissue to a metal implant, wherein the implantcomprises a metal implant having a porous region, wherein said porousregion exhibits a nano-textured surface, and a calcified material layercoating the nano-textured surface. In one embodiment the average maximumheight of the protrusions comprising the nano-textured surface isselected from a range of about 50 nm to about 200 nm. The nanotexturedsurface can be prepared using standard techniques including anodizationof the metal surface or by chemical etching of the metal surface.

In one particular embodiment a construct for enhancing the attachment ofsoft tissue to a metal implant is provided. The construct comprises ametal implant comprising a porous region, wherein said porous regionexhibits a nano-textured surface, and a biocompatible polymer matrixcoating the nano-textured surface, wherein the biocompatible polymermatrix comprises a naturally occurring extracellular matrix and anexogenous biocompatible inorganic material. In one aspect of the presentinvention the naturally occurring extracellular matrix comprisesintestinal submucosa in gel form, and the biocompatible inorganicmaterial is dispersed within the intestinal submucosa. The exogenousbiocompatible inorganic material in accordance with one embodimentcomprises hydroxyapatite and in a further embodiment the gelledintestinal submucosa is coated onto the nano-textured surface and dried.In an alternative embodiment the biocompatible polymer matrix comprisesa biocompatible polymer and an exogenously added osteo-inductive agent,and optionally, exogenously added hydroxyapatite.

In one embodiment the composite implant further comprises an extenderlayer coupled to a metal implant and in contact with a biocompatiblepolymer matrix present on the metal implant, wherein said extender layercomprises a submucosal matrix, and a synthetic portion coupled to thesubmucosal matrix. More particularly the synthetic portion comprises amesh member wherein said mesh member is coated with a comminutednaturally occurring extracellular matrix.

In another embodiment a composite bioprosthetic construct is provided.In this embodiment the construct comprises a metal implant thatcomprises a porous region, wherein said porous region exhibits anano-textured surface, a calcified material layer coating thenano-textured surface; and a scaffold layer comprising a biocompatiblepolymer matrix and growth factors, wherein at least a portion of saidscaffold layer is in contact with said calcified material layer. In oneembodiment the calcified material layer comprises hydroxyapatite and abiocompatible polymer matrix, and optionally an exogenously addedosteo-inductive agent. In one embodiment the calcified material layercomprises a naturally occurring extracellular matrix, including forexample a submucosal matrix. In a further embodiment an extender layercoupled to the scaffold layer of the construct, wherein the extenderlayer comprises a submucosal matrix, and a synthetic portion coupled tothe submucosal matrix.

The present invention also encompasses kits for repairing joints andattaching soft tissues to prosthesis. In one embodiment a kit forrepairing a diarthrodial joint comprises a metal implant comprising aporous region, wherein the porous region exhibits a nano-texturedsurface, a biocompatible polymer matrix coating the nano-texturedsurface, wherein the biocompatible polymer matrix comprises a naturallyoccurring extracellular matrix and exogenously added biocompatibleinorganic material, and an extender graft comprising a naturallyoccurring extracellular matrix, and a mesh member coupled to thenaturally occurring extracellular matrix. In accordance with oneembodiment the biocompatible inorganic material comprises nano-scalehydroxyapatite crystals.

The present invention is also directed to a method of attaching softtissue to a metal implant. In one embodiment the method comprises thesteps of first providing a metal implant construct, wherein saidconstruct comprises 1) a metal implant comprising a porous region thatexhibits a nano-textured surface, and 2) a biocompatible polymer matrixcoating the nano-textured surface, wherein the biocompatible polymermatrix comprises a naturally occurring extracellular matrix and anexogenously added biocompatible inorganic material. At least a portionof a scaffold layer is then coupled to the metal implant construct in amanner that places it in contact with the biocompatible polymer matrix.In one embodiment the scaffold layer comprises a biocompatible polymermatrix and a growth factor. The proximal end of an extender portion isthen attached to the scaffold layer, wherein said extender portioncomprises a submucosal matrix, and a synthetic portion coupled to thesubmucosal matrix and attaching the distal end of the extender portionto a patient's soft tissue. In one embodiment the synthetic portioncomprises a mesh member wherein said mesh member is coated with anaturally occurring extracellular matrix.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 represents a schematic drawing of a composite implant for softtissue enthesis regeneration. The composite implant of this embodimentcomprises five layers, with layers 1-3 representing the materials and/orsurface treatments which, upon implantation of the composite, willregenerate calcified tissue which is mechanically interlocked with theimplant surface, and layers 4 and 5 representing materials which, uponimplantation of the composite, will bind the patient soft tissue to themechanically-interlocked calcified tissue. Individually, the layers areas follows: layer 1 represents the metal implant comprising a poroussurface region; layer 2 represents a nano-textured surface layer (e.g.,a nanomaterial coating/nanosurface roughness); layer 3 represents acalcified matrix; layer 4 represents a bioactive uncalcified matrix andlayer 5 represents a cell modulating layer.

FIG. 2 represents a schematic drawing of a diarthrodial joint prosthesisand a composite implant for soft tissue enthesis regeneration. The metalimplant (10) comprises a tibial component (12) of a knee jointprosthesis and the soft tissue to be attached is a ligament or tendon(14). The metal implant is provided with a porous region, the surface ofwhich is provided with a nano-textured roughness (16). The nano-texturedsurface is coated with a calcified matrix (18) and the calcified matrixis bound to a scaffold layer (20) that comprises a bioactive uncalcifiedmatrix. The scaffold layer is coupled to an extender (22) that is inturn attached to a ligament or tendon (14).

DETAILED DESCRIPTION Definitions

In describing and claiming the invention, the following terminology willbe used in accordance with the definitions set forth below.

As used herein the term “bioactive agents” includes one or more of thefollowing: growth factors selected from the group consisting of membersof the transforming growth factor-beta (TGF-b) superfamily, such asmembers of the bone morphogenetic protein (BMP) family (including BMP-2,BMP-4, BMP-6, BMP-12, and BMP-14 and ADMP) and members of the growth anddifferentiation factor (GDF) family (including GDF4, GDF5, GDF6, GDF7,and GDF8); members of the fibroblast growth factor (FGF) family; membersof the insulin-like growth factor (IGF) family; members of theplatelet-derived growth factor family (PDGF); members of the epidermalgrowth factor (EGF) family; angiogenic growth factors such as vascularendothelial growth factors (VEGF); cytokines such as members of theinterleukin (IL) family and colony stimulating factors (CSF); proteinssuch as members of the hedgehog family of proteins, members of theparathyroid hormone (PTH) and PTH-related family of proteins (PTHrPs);skeletal tissue extracellular matrix components such as proteoglycans,glycosaminoglycans, hyaluronic acid, chondroitin sulfate, decorin,dermatan sulfate, keratan sulfate, tenascin, fibronectin, vitronectin,and bone sialoprotein; other factors such as thromboelastin, thrombin,heparin, various ligands, and members of the integrin family; smallpeptides that modulate cell attachment such as RDG peptides, smallpeptide collagen analogues (see U.S. Pat. Nos. 5,354,736 and 5,635,482,the disclosures of which are incorporated herein), small peptidefibronectin analogues, small peptide bone sailoprotein analogues,integrin-binding domains, and heparin-binding domains; small peptidesthat effect the upregulation of specific growth factors such asthrombin-derived peptides (e.g. Chrysalin, available from ChrysalisBioTechnology and Orthologic Corp). Additionally, the term “bioactiveagents” also includes therapeutic drugs (such as antibiotics,antimicrobials, steroidal and non-steroidal analgesic andanti-inflammatory drugs, anti-rejection agents such asimmune-suppressants and anti-cancer drugs) or other therapeutic agentsthat can directly effect gene regulation such as DNA, DNA fragments, orDNA plasmids, RNA, RNA fragments, micro RNAs (miRNAs), and shortdouble-stranded RNA for post-translational RNA interference (RNAi).

As used herein the term “biologically derived agents” include one ormore of the following: bone (autograft, allograft, and xenograft) andderivates of bone; cartilage (autograft, allograft, and xenograft),including, for example, meniscal tissue, and derivatives; ligament(autograft, allograft, and xenograft) and derivatives; derivatives ofintestinal tissue (autograft, allograft, and xenograft), including forexample submucosa; derivatives of stomach tissue (autograft, allograft,and xenograft), including for example submucosa; derivatives of bladdertissue (autograft, allograft, and xenograft), including for examplesubmucosa; derivatives of alimentary tissue (autograft, allograft, andxenograft), including for example submucosa; derivatives of respiratorytissue (autograft, allograft, and xenograft), including for examplesubmucosa; derivatives of genital tissue (autograft, allograft, andxenograft), including for example submucosa; derivatives of liver tissue(autograft, allograft, and xenograft), including for example liverbasement membrane; derivatives of skin tissue; platelet rich plasma(PRP), platelet poor plasma (PPP), bone marrow aspirate, demineralizedbone matrix, whole blood, fibrin, and blood clot. Purified ECM and othercollagen sources are also intended to be included within “biologicallyderived agents.”

As used herein the term “cells”, absent any further elaboration orcharacterization, includes one or more of the following: chondrocytes;fibrochondrocytes; osteocytes; osteoblasts; osteoclasts; synoviocytes;bone marrow cells; mesenchymal cells; stromal cells; stem cells;embryonic stem cells; precursor cells derived from adipose tissue;peripheral blood progenitor cells; stem cells isolated from adulttissue; genetically transformed cells; a combination of chondrocytes andother cells; a combination of osteocytes and other cells; a combinationof synoviocytes and other cells; a combination of bone marrow cells andother cells; a combination of mesenchymal cells and other cells; acombination of stromal cells and other cells; a combination of stemcells and other cells; a combination of embryonic stem cells and othercells; a combination of precursor cells isolated from adult tissue andother cells; a combination of peripheral blood progenitor cells andother cells; a combination of stem cells isolated from adult tissue andother cells; and a combination of genetically transformed cells andother cells. If other cells are found to have therapeutic value in theorthopedic field, it is anticipated that at least some of these cellswill have use in the present invention, and such cells should beincluded within the meaning of “cell” and “cells” unless expresslylimited otherwise. Illustratively, in one example of embodiments thatare to be seeded with living cells such as osteoblasts, a sterilizedimplant may be subsequently seeded with living cells and packaged in anappropriate medium for the cell type used. For example, a cell culturemedium comprising Dulbecco's Modified Eagles Medium (DMEM) can be usedwith standard additives such as non-essential amino acids, glucose,ascorbic acid, sodium pyruvate, fungicides, antibiotics, etc., inconcentrations deemed appropriate for cell type, shipping conditions,etc. Alternatively, the living cells can be derived from a mammalianpatient at the point-of-care and combined with one or more elements of acomposite implant prior to implantation.

As used herein the term “biocompatible polymers” is intended to includeboth synthetic polymers and biopolymers (e.g. collagen), and a“biocompatible polymer matrix” refers to a mass formed by such polymers.Examples of biocompatible synthetic polymers include: polyesters of[alpha]-hydroxycarboxylic acids, such as poly(L-lactide) (PLLA) andpolyglycolide (PGA); poly-p-dioxanone (PDO); polycaprolactone (PCL);polyvinyl alcohol (PVA); polyethylene oxide (PEO); polymers disclosed inU.S. Pat. Nos. 6,333,029 and 6,355,699; co-polymer or a mixture ofpolymers and/or co-polymers such as polymer networks ofpoly(acrylamide-co-ethylene glycol/acrylic acid) orpoly(lysine-(lactide-ethylene glycol)) or any other biocompatiblepolymer, co-polymer or mixture of polymers or co-polymers that areutilized in the construction of prosthetic implants or prostheticimplant coatings. Examples of commercially available syntheticbiocompatible polymers include Prolene™, Vicryl™, Mersilene™, andPanacryl™. In addition, as new biocompatible, bioresorbable materialsare developed, it is expected that at least some of them will be usefulmaterials from which orthopedic devices may be made. It should beunderstood that the above materials are identified by way of exampleonly, and the present invention is not limited to any particularmaterial unless expressly called for in the claims.

As used herein the term “biocompatible inorganic materials” includematerials such as hydroxyapatite, all calcium phosphates,alpha-tricalcium phosphate, beta-tricalcium phosphate, calciumcarbonate, barium carbonate, calcium sulfate, barium sulfate, polymorphsof calcium phosphate, sintered and non-sintered ceramic particles, andcombinations of such materials. Additionally, “biocompatible inorganicmaterials” also include salts of di- or tri-valent metal cations such ascopper, iron, manganese, and magnesium with anions such as, for example,chlorides and sulfates.

As used herein the term “collagen-based matrix” refers to extracellularmatrices that comprise collagen fibers and include both naturallyoccurring extracellular matrices as well as reconstituted collagenmatrices.

As used herein the term “naturally occurring extracellular matrix”includes isolated natural extracellular matrices (such as intestinalsubmucosa) in their native configuration, from a mammalian organ bodywall (such as, for example, stomach wall, intestinal wall bladder wall,liver or lung basement membrane), as well as natural extracellularmatrix material that has been subjected to delamination, comminutation,fluidization, and gelation. However, it is not within the definition ofa naturally occurring extracellular matrix to extract and purify thenatural fibers and refabricate a matrix material from purified naturalfibers. Such a refabricated matrix is referred to as a “reconstitutedcollagen matrix” or “reconstituted ECM matrix”.

As used herein the term “submucosal matrices” refers to naturalextracellular matrices, known to be effective for tissue remodeling,that have been isolated in their native configuration.

As used herein the term “exogenous” or “exogenously added” designatesthe addition of a new component to a composition, or the supplementationof an existing component already present in the composition, usingmaterial from a source external to the composition.

As used herein the term “calcification-inducing layer” or like termsrelate to a composition of matter that comprises agents that activelyinduce the calcification of the composition when the composition isimplanted in a patient.

As used herein the term “apatite” refers to minerals defined by thegeneral formula: A₅(B)₃ (OH, F, Cl or CO₃), wherein the A component ofthe formula represents a metal cation selected from the group consistingof calcium, barium, strontium, and cerium. The B component can be eithera phosphate (PO₄) or carbonate (CO₃) anion groups.

As used herein the term “fluidized matrices” and like terms, encompasscollagen-based matrices (including for example intestinal submucosa)that have been modified to allow the material, at room temperature, toflow and conform to the shape of its container.

As used herein the term “gelled matrices” and like terms, encompasscollagen-based matrices (including for example intestinal submucosa)that have been modified to exhibit the properties of a jelly (i.e. aviscous material that generally maintains its shape, but is capable ofbeing molded to different shapes) at room temperature.

Embodiments

One aspect of the present invention is directed to a novel compositeimplant and method for regenerating soft tissue enthesis. The compositesystem is composed of different biologic or non-biologic materialswherein the composite system is interposed between soft tissue and ametallic or hard plastic prosthesis. After insertion into a patient, thecomposite system is remodeled over time to regenerate a differentiatedtransition zone of attachment that is biologically similar to thenaturally occurring transition zone of attachment of a soft tissue tobone in the vicinity of a diarthrodial joint. Accordingly, the novelcomposite implants of the present invention can be used to attachtendons, ligaments, joint capsules, and other soft tissue to metallic orplastic implants to minimize the mechanical stress concentrations at theattachment site and maximize the soft tissue pull out force from theprosthetic implant.

In accordance with one embodiment the composite implant comprises twomain regions: the mechanical interlock region and the bioactive region.The mechanical interlock region comprises relatively hard and stiffcomposites and functions to regenerate calcified tissue which ismechanically interlocked with the porous texture at the implant surface.This regenerated, mechanically-interlocked calcified tissue provides astrong attachment to the metallic implant. The bioactive regioncomprises softer composites, and functions to connect the calcifiedtissue of the mechanical interlock region to soft tissue, such as atendon, ligament, or joint capsule.

The mechanical interlock region binds non-metal calcified material withthe metal surface by promoting bone regeneration and ingrowth into themetal. In accordance with one embodiment, three layers contribute to thefunctionality of the mechanical interlock region. The first layercomprises a porous metal surface, the second layer is a nanomateriallayer that provides nano-surface roughness, and the third layercomprises a calcified or calcification-inducing layer.

Techniques for producing metallic implants that comprise a porous regionare known to those skilled in the art and include the use of metal (i.e.titanium) plasma sprays, metallic bead coatings (i.e. Porocoat® PorousCoating), the attachment of a porous fiber mesh material, (such as thetype described in Rostoker, et al's U.S. Pat. No. 3,906,550), areticulated metallic porous material with interconnected pores (such as,for example, Trabecular Metal® or Hedrocel®) or other metallic porousmaterial. In accordance with one embodiment the metal implant isprovided with a porous region comprising a Porocoat® Porous Coating. Inthis embodiment the coating is composed of a powder of nearly spherical,metallic beads of approximately 150 μm to 300 μm in diameter that areadhered to the desired location on the metal implant by, for example, asintering process. This technique results in a multi-layered, beadedcoating that is open, with interconnected pores, and extremely rough,and provides a strong initial fixation upon implantation. The density ofpores is inversely related to diameter of spherical metallic beads usedfor coating the metallic implant. In one embodiment the average valueporosity of the porous regions is somewhere in the range of about 30% toabout 80%. In one embodiment the average value porosity of the porousregions is somewhere in the range of about 70% to about 80%. In anotherembodiment the average value porosity of the porous regions is somewherein the range of about 40% to about 50%. In another embodiment averagevalue porosity of the porous regions is somewhere in the range of about30% to about 35%. In one embodiment the coating has a graded density,increasing in porosity near the outer surface and increasing in densityand strength near the implant surface. In one embodiment the maximumdiameter of the pores ranges from about 10 μm to about 800 μm in size.In another embodiment the maximum diameter of the pores ranges fromabout 100 μm to about 400 μm. This size is sufficient for ingrowth ofbone, yet the spheres are small enough to provide a rough surface. Inone embodiment the pores are randomly distributed across the porousregion and the pores have an irregular shape.

In accordance with one embodiment, the surface of the porous region ismodified to exhibit a nano-textured surface. This can be accomplished byeither adhering nanoparticles to the metal surface of the porous regionor by etching the original surface to provide a nanotexture. As definedherein a nano-textured surface relates to a surface that has beenroughened to exhibit a series of cavities and protrusions wherein themaximum distance from the highest point to the lowest point on theporous region is less than 200 nanometers. In one embodiment the averageheight of the protrusions ranges anywhere from about 20 nm to about 200nm, and in one embodiment the average height of the protrusions rangesanywhere from about 30 nm to about 120 nm, in another embodiment theaverage height of the protrusions ranges anywhere from about 40 nm toabout 100 nm and in another embodiment the average height of theprotrusions is less than 100. In one embodiment the nano-texturedsurface comprises a series of protrusions wherein the minimum height ofthe protrusions is 50 nm and the maximum height of the protrusions isabout 150 nm as measured from the lowest point on the porous region. Inone embodiment the protrusions are irregularly shaped and distributedrandomly on the textured surface. The distance between protrusions (asmeasured from the center of one protrusion to the center of itsneighbor) can range anywhere from about 25 nm to about 500 nm, and inone embodiment the average distance between protrusions of thenano-textured surface is a value selected from the range of about 50 nmto about 250 nm

In accordance with one embodiment a metallic implant device is preparedthat comprises a porous region, wherein the metallic implant device isfurther modified to display a nanosurface roughness on the device, atleast on the area that includes the porous region. In one embodiment thenanosurface roughness on the implant surface is prepared by anodizationat low voltage for short period. For example, anodization of metallicsurfaces (Ti metal or Ti-6Al-4V alloy) at 20 volts for 1, 3 and 5minutes after pretreatment of the samples with an acid mixture (2 ml of48% HF+3 ml of 70% HNO₃ in 100 ml of DI water) produces a nanosurfaceroughness in accordance with the present invention. Nano-roughness canalso be achieved via other means such as chemical etching or adheringnano particles to the metal surface of the device. Additional methods ofpreparing a nanosurface topography are described in U.S. Pat. Nos.6,136,369, 6,143,948 and 6,344,061 as well as published US applicationsUS 20040167632 and US 20040167633, the disclosures of which areincorporated herein. The nanosurface roughness mimics the jigsaw-likeinterlocking between calcified fibrocartilage and bone in the naturalentheses.

Within the mechanical interlock region, the nanosurface roughened areais in contact with a calcified material layer or acalcification-inducing layer. In one embodiment the calcified materiallayer consists of a pure hydroxyapatite/calcium containing mineral. Inanother embodiment the calcified material layer comprises abiocompatible polymer matrix and a hydroxyapatite/calcium containingmineral layer formed either as two or more discrete layers or as amixture of the mineral and polymer. In another embodiment the calcifiedmaterial layer comprises a mixture of a hydroxyapatite/calciumcontaining mineral and a biocompatible polymer matrix. In accordancewith one embodiment cycles of alternative pressure and suction is beapplied to fill the porocoat structure on the metallic implant with gelor fluidized form of natural extracellular matrix or collagen-basedmatrices.

In one embodiment the calcification-inducing layer of the mechanicalinterlock region comprises a biocompatible polymer matrix that is boundto, or entraps within the matrix, bioactive agents that actively inducethe calcification of this tissue. In accordance with one embodiment thebiocompatible polymer matrix is selected from the group consisting ofnatural and reconstituted collagen matrices, and naturally occurringextracellular matrices, including submucosal matrices. Extracellularmatrices isolated from various tissues are known to be effective fortissue remodeling, and include, but are not limited to, extracellularmatrices isolated from mammalian intestine, stomach, bladder,alimentary, respiratory, and genital submucosa. See, e.g., U.S. Pat.Nos. 4,902,508, 6,171,344, 6,099,567, and 5,554,389, the disclosures ofwhich are hereby incorporated by reference. These tissues are referredto generally as “submucosal matrices” and comprise highly conservedcollagens, glycoproteins, proteoglycans, and glycosaminoglycans.Additionally, other known extracellular matrices, for example laminapropria and stratum compactum, may also be used in accordance with thepresent invention.

In one embodiment the calcified material layer/calcification-inducinglayer comprises intestinal submucosa, and in one embodiment the layercomprises small intestinal submucosa of a warm blooded vertebrate. Inone embodiment, the material comprises the tunica submucosa along withthe lamina muscularis mucosa and the stratum compactum of a segment ofintestine, said layers being delaminated from the tunica muscularis andthe luminal portion of the tunica mucosa of said segment. Such amaterial is referred to herein as intestinal submucosa (SIS). Inaccordance with one embodiment of the present invention the intestinalsubmucosa comprises the tunica submucosa along with basilar portions ofthe tunica mucosa of a segment of intestinal tissue of a warm-bloodedvertebrate. While porcine SIS is widely used, it will be appreciatedthat intestinal submucosa may be obtained from other animal sources,including cattle, sheep, and other warm-blooded mammals.

The preparation of SIS from a segment of small intestine is detailed inU.S. Pat. No. 4,902,508, the disclosure of which is expresslyincorporated herein by reference. A segment of intestine is firstsubjected to abrasion using a longitudinal wiping motion to remove boththe outer layers (particularly the tunica serosa and the tunicamuscularis) and the inner layers (the luminal portions of the tunicamucosa). Typically the SIS is rinsed with saline and optionally storedin a hydrated or dehydrated state until use. Currently there aremultiple patents and publications that describe in detail thecharacteristics and properties of intestinal submucosa (SIS). See, forexample, U.S. Pat. Nos. 4,352,463, 4,902,508, 4,956,178, 5,281,422,5,372,821, 5,445,833, 5,516,533, 5,573,784, 5,641,518, 5,645,860,5,668,288, 5,695,998, 5,711,969, 5,730,933, 5,733,868, 5,753,267,5,755,791, 5,762,966, 5,788,625, 5,866,414, 5,885,619, 5,922,028,6,056,777, and WO 97/37613, the disclosure of which is incorporatedherein by reference. SIS, in various forms, is commercially availablefrom Cook Biotech Incorporated (Bloomington, Ind.), DePuy Orthopaedics(Warsaw, Ind.), and Biomet, Inc. (Warsaw, Ind.). Further, U.S. Pat. No.4,400,833 to Kurland and PCT publication having InternationalPublication Number WO 00/16822 provide information related tobioprosthetics and are also incorporated herein by reference.

Naturally occurring extracellular matrices can be prepared as “fluidizedforms” comprising solutions or suspensions of the matrix by comminutingand/or digesting the matrix with a protease, such as trypsin or pepsin,or by an acid (such as, for example, ascetic acid) for a period of timesufficient to solubilize said tissue and form a substantiallyhomogeneous solution or suspension. In one embodiment an intestinalsubmucosa matrix is used as the starting material, and the material iscomminuted by tearing, cutting, grinding, shearing and the like. In oneembodiment, the intestinal submucosa is ground in a frozen orfreeze-dried state to prepare a comminuted form of SIS. This grindingprocess produces a fine powder-like comminuted SIS upon drying.Alternatively, comminuted SIS can also be obtained by subjecting asuspension of pieces of the submucosa to treatment in a high speed (highshear) blender, and dewatering, if necessary, by centrifuging anddecanting excess water to produce finely comminuted SIS fibers. Thecomminuted submucosa fibers can be dried and further ground to form asubmucosa powder. Thereafter, it can be hydrated, that is, combined withwater or buffered saline and optionally other pharmaceuticallyacceptable excipients to form a tissue graft composition as a fluidhaving a viscosity of about 2 to about 300,000 cps at 25° C. Higherviscosity graft compositions having a gel or paste consistency, can beprepared from the SIS solutions/suspensions by adjusting the pH of suchsolutions/suspensions to about 6.0 to about 7.0. The presentcompositions can be sterilized using art-recognized sterilizationtechniques such as exposure to ionizing radiation.

Alternatively, in one embodiment gelled submucosa matrices are preparedthrough the use of heat to dissemble the collagen-based materialfollowed by cooling the material. In accordance with one embodimentnaturally occurring extracellular matrices or even pure collagen can beformed as a gel by subjecting the material to temperatures ranging fromabout 30° C. to about 70° C. for a predetermined length of time. In oneembodiment the material is heated at about 30° C. to about 60° C. for 10to 20 minutes, and in one embodiment the material is heated at 60° C.for 20 minutes. The material is then allowed to cool, typically to roomtemperature to form the submucosa gel. Use of fluidized, gelatinized, orheated collagen-based extracellular matrices (such as SIS) for coatingorthopedic implants not only enhances the uniformity of coating, byreducing uncoated gaps on the surface, but it also enhances theinterlocking properties of the material. For example, the use of gelledSIS material enhances the interlocking properties of the intestinalsubmucosa 3 to 4 fold. This also prevents loss of the coating duringhandling and transportation.

In one embodiment the calcified material layer comprises a naturallyoccurring extracellular matrix that is modified to include one or moreexogenously added bioactive agents or biocompatible inorganic materials.In one embodiment the calcified material layer comprises a naturallyoccurring extracellular matrix that is modified to include exogenouslyadded apatite. In one embodiment the exogenously added apatite includescompounds of the formula: Ca₅(PO₄)₃(OH, F, Cl or CO₃). Examples of othersuitable biocompatible inorganic materials for use in the presentinvention include: hydroxyapatite, all calcium phosphates,alpha-tricalcium phosphate, beta-tricalcium phosphate, calciumcarbonate, barium carbonate, calcium sulfate, barium sulfate, polymorphsof calcium phosphate, ceramic particles, and combinations of suchmaterials. In accordance with one embodiment the added biocompatibleinorganic material is hydroxyapatite. In one embodiment thehydroxyapatite is in particulate form (having a mean diameter of lessthan 500 nm, or less than 250 nm or less than 150 nm), wherein theparticles are dispersed on the surface and/or within the extracellularmatrix.

Sonication of conventional hydroxyapatite (HA) powders (having particleswith a mean diameter in the micron range) in water for 6 hours providesnano-HA dispersions. This treatment stabilizes HA dispersions in water,and the dispersions remained stable for several days to weeks aftersonication treatment. Mean particle diameters of the dispersions madeout of conventional HA powders were 1.678 μm with approximately 50% ofthe particles having diameters less than 1.5 μm. Whereas, thecorresponding values for sonicated HA were 0.118 μm with approximately50% of the particles having diameters less than 0.098 μm. Further, X-raydiffraction analysis suggests that the crystalline phases of HA are notaffected by aqua-sonication. In accordance with one embodiment, the HAis hydrothermally treated (for example at about 200° C. for 20 hoursunder pressure) and then sonicated for 2 hours to provide nano-HAdispersions. Mean particle diameters of nano-hydroxyapatite dispersionsproduced by this method were about 86.75 nm with approximately 50% ofthe particles having diameters less than about 83.50 nm. A completesurface coating on implants can be achieved with nano-HA dispersions.

In one embodiment the nano-textured surface is coated with a calcifiedmaterial layer that comprises a biocompatible polymer and abiocompatible inorganic material. The biocompatible polymer may comprisea natural or reconstituted collagen matrix and may be selected from anaturally occurring extracellular matrix. In one embodiment thecalcified material layer comprises a collagen matrix and nano-scalehydroxyapatite crystals, wherein said crystals are entrapped or bound tothe collagen matrix material.

In accordance with one embodiment a calcified material layer is providedas the third layer of the mechanical interlock region, wherein thecalcified material layer comprises a naturally occurring extracellularmatrix and hydroxyapatite. In one embodiment the calcified materiallayer comprises a naturally occurring extracellular matrix in fluid orgel form combined with nanoparticulate hydroxyapatite (HA). In oneembodiment the calcified material layer comprises gelled intestinalsubmucosa and nanoparticulate HA, wherein the nanoparticulate HA isdispersed within the gelled submucosa matrix and the matrix is coatedonto the nano-textured surface and dried. Preparation of emulsions withSIS powder and nanoparticulate HA in dispersion form @ about a 1:0.25ratio of SIS to HA (dry weight %) followed by gelatinization at 60° C.for 20 minutes provides an effective coating that not only mimics thenatural entheses (i.e., attachment site between implant and tendon/softtissues) tissues but also enhances the interlocking characteristics ofSIS on metals. Further, fibrous collagen-based foam scaffolds with nano-or micro-scale HA crystals deposited on the fibers can be used (e.g.mineralized SIS, DePuy Spine's Healos®). The calcified material layercan also contain exogenously added bioactive agents, biologicallyderived agents, cells, or other biocompatible inorganic materials. Inone embodiment the calcified material layer comprises a biocompatibleinorganic material selected form the group consisting of copper (II)sulfate pentahydrate (CuSO₄. 5H₂O), copper (II) chloride hydrate(CuCl₂.2H₂O), iron-dextran, iron (II) sulfate heptahydrate (FeSO₄.7H₂O), manganese (II) sulfate monohydrate (MnSO₄, H₂O), magnesiumsulfate heptahydrate (MgSO₄. 7H₂O), magnesium phosphate dibasictrihydrate (MgHPO₄. 3H₂O), glycine, proteoglycans, Vit A, Vit B, Vit C,Vit D and cicosapentaenoic acid. The addition of these exogenously addedmaterials is intended to effect cell proliferation, cell differentiationand the synthesis, modification, and crosslinking of extracellularcomponents.

In accordance with one embodiment the calcified material is applieddirectly to the implant surface in the absence of the nano-texturedsurface. In accordance with one embodiment apatite is applied directlyto the implant surface in the absence of a nano-textured surface.Application of apatite onto the implant can be achieved using techniquesknown to those skilled in the art as described in U.S. Pat. Nos.6,569,489, 6,139,585, 6,736,849 and published US Patent applications20040153165, the disclosures of which are incorporated herein. When theapatite layer is applied directly onto the implant surface the crystalsmay be either in the nano- or micrometer size range. In anotherembodiment one or more bioactive agents are applied in the absence of apolymer matrix either directly onto the implant or onto a nano-texturedsurface layer prepared on the implant. Coating a prosthesis withbioactive agents can be accomplished using techniques described in U.S.Pat. No. 5,824,651, the disclosure of which is incorporated herein.

In accordance with one embodiment, lysine is added to the calcifiedmaterial layer to increase the dispersion of HA particles in thecollagen based bioscaffold. Addition of lysine in an amount ranging fromabout 0.01% to about 0.6%, and in one embodiment ranging from about0.01% to about 0.3%, improves dispersion of HA in collagen-basedmatrices.

In another embodiment the metallic implant surface (with or withoutnano-texturing) is coated with a calcification-inducing layer, whereinthe coated material does not include calcified material. In thisembodiment the calcification-inducing layer comprises a biocompatiblepolymer and a bioactive agent. For example, in one embodiment thebiocompatible polymer is in the form of a thin coating of a syntheticpolymer, co-polymer, polymer network, or a mixture thereof, on themetallic implant surface, wherein the coating entraps one or morebioactive agents that will induce the regeneration of calcified tissueupon implantation into a patient. In one embodiment the biocompatiblepolymer comprises a collagen matrix. The calcification-inducing layermay also include one or more exogenously added biocompatible inorganicmaterials, biologically derived agents, or cells.

In accordance with one embodiment of the present invention a constructis provided for enhancing the attachment of soft tissue to a metalimplant. More particularly, the construct allows for the creation of adifferentiated transition zone at the insertion site of soft tissues(such as tendons and ligaments) into a metal prosthetic device. In oneembodiment, the construct comprises a metal implant comprising a porousregion, wherein said porous region exhibits a nano-textured surface. Theconstruct is further provided with a calcified material layer, orcalcification-inducing layer, that coats the nano-textured surface. Thisconstruct provides a mechanical interlocking region that binds non-metalcalcified material with the metal surface by promoting a jigsaw-likeunion between the calcified material and the metal surface.

In accordance with one embodiment of the present invention a constructfor enhancing attachment of soft tissue to a metal implant is provided,wherein the construct comprises a metal implant comprising a porousregion, wherein said porous region exhibits a nano-textured surface anda naturally occurring extracellular matrix fixed to the metal implantand in contact with the nano-textured surface. In one embodiment thenaturally occurring extracellular matrix is formed as fluid or gel,mixed with one or more biocompatible inorganic materials or bioactiveagents and coated onto the nano-textured surface. In one embodiment thenaturally occurring extracellular matrix comprises intestinal submucosain gel form, wherein the biocompatible inorganic material or bioactiveagent is dispersed within the submucosal matrix and coated and dried onthe nano-textured surface.

In accordance with one embodiment a composite system for attaching softtissue to a metal prosthesis is provided. In one embodiment thecomposite system comprises a five-layer composite (FIG. 1). These layersinclude (from implant toward soft tissue): (1) a metal prosthesiscomprising a porous region, (2) a nanomaterial coating layer and/ornanosurface roughness formed on the porous region, (3) a calcifiedmaterial layer in contact with the nano-textured surface, (4) abioactive uncalcified scaffold layer bound to the calcified materiallayer, and (5) a cell modulating extender layer bound to the uncalcifiedscaffold layer. The first three layers are comprised of relatively hardand stiff composite materials, and provide the mechanical interlock tothe metallic implant. The last two layers (“the cell modulating layers”)are comprised of softer composites, and provide a bioactive regionconnecting calcified tissue to soft tissue. Within the bioactive region,both the layers typically comprise a collagen-based material. The cellmodulating layers may comprise biocompatible inorganic materials and/orbioactive agents that aid in cell recruitment, proliferation, migration,differentiation, and extracellular matrix molecule synthesis andassembly. Two or more of the five aforementioned layers can bephysically collapsed into one layer and can carry all the requiredconstituents within that one layer. Further, one or more of theaforementioned layers can be eliminated as long as it does notcompromise the regeneration of the differentiated soft tissue enthesis.

In accordance with one embodiment a composite bioprosthetic device isprovided for replacing or repairing a diarthrodial joint. The devicecomprises a metal implant formed as a component for a diarthrodialprosthesis. The composite implant of the present invention can be usedto attach soft tissues (including tendons, ligaments and joint capsules)to metal implants in various location including the knee, hip shoulderand spine. In one embodiment the composite construct is used to attachspinal ligaments to spinal components. In another embodiment thecomposite structure is used to attach a knee or hip capsule to a metalimplant. In one embodiment the metal implant is formed as a tibialcomponent for a knee joint prosthesis to allow attachment of knee jointtendons and ligaments. The metal implant is provided with a porousregion located on the implant at a position where soft tissue will beattached to the prosthetic device. In one embodiment, the metal implantis further provided with a nano-texture surface on at least the portionof the metal implant that comprises the porous region. The nano-texturesurface can be coated or adhered onto the metal implant using nano-sizedparticles and techniques known to those skilled in the art. In analternative embodiment the nano-textured surface can be prepared byetching the surface of the implant using standard techniques known tothe skilled practitioner. A calcified material layer, or acalcification-inducing layer, is bound to the nano-textured surface,with the calcified/calcifying layer being bound to a scaffold layer. Thescaffold layer comprises a biocompatible polymer matrix and bioactiveagents. In one embodiment only a portion of the scaffold layer is incontact with the calcified material layer/calcification-inducing layer,with the remaining unattached scaffold portion extending away from thecalcified material layer/calcification-inducing layer.

The scaffold layer provides an uncalcified zone that promotes cellrecruitment, proliferation, migration, differentiation, andextracellular matrix molecule synthesis and assembly. The scaffoldtypically comprises a biocompatible matrix that further comprisesbioactive agents. In accordance with one embodiment the biocompatiblematrix comprises collagen fibers.

In one embodiment the scaffold layer comprises a naturally occurringextracellular matrix, such as intestinal submucosa. The scaffold can beformed into an elongated shape (such as a rectangular structure) havingtwo lateral side portions and two end portions, wherein the lateral sideportions each have a greater length than either of the two end portions.Typically the scaffold will be seeded with cells. In accordance with oneembodiment the scaffold is also embedded with one or more biologicallyderived agents and/or biocompatible inorganic materials. In accordancewith one embodiment a first end portion of the scaffold layer isattached to the metal implant in a manner that places at least a portionof the scaffold layer in direct contact with the calcified materiallayer/calcification-inducing layer. The second end portion of thescaffold extends away from the calcified materiallayer/calcification-inducing layer.

In a further embodiment, the composite bioprosthetic device is providedwith an extender layer, wherein only a portion of the extender layer iscoupled to the scaffold layer. The extender layer of the bioprostheticdevice functions to provide additional tissue for linking the prosthesisto the soft tissues of the patient. In one embodiment the extendercomprises a naturally occurring extracellular matrix, and a syntheticportion bound to the extracellular matrix. In one embodiment theextender layer has an elongate shape, wherein one end of the extenderlayer is coupled the second end portion of the scaffold layer. Both thescaffold layer and the extender layer components of the compositebioprosthetic device can be formed from naturally occurringextracellular matrix such as intestinal tissue, however the extenderlayer further comprises a synthetic component that adds strength to theextender layer. In accordance with one embodiment the synthetic portioncomprises a mesh member, and in a further embodiment the mesh member iscoated with naturally occurring extracellular matrix. In one embodimentthe mesh is coated with comminuted, fluidized or gelled intestinalsubmucosa. An extender layer suitable for use in the present inventionis described in U.S. Pat. No. 6,638,312, the disclosure of which isincorporated herein.

The mesh can also be treated to enhance the hydrophilicity of the meshand enhance its binding to hydrophilic extracellular matrices. Inaccordance with one embodiment the mesh is chemically treated by use ofhydrolysis or by use of an amidation technique. In one embodiment thesurface of the synthetic layer was treated with a gas plasma processingtechnique, including for example treating the surface of the syntheticlayer with an ammonia plasma or an oxidative plasma.

In accordance with one embodiment the extender layer is prepared bytreating a surface of a synthetic layer to increase the hydrophilicityof the surface, positioning the treated synthetic layer between a firstlayer of naturally occurring extracellular matrix material and a secondlayer of naturally occurring extracellular matrix material to make anassembly, and operating a press to exert positive pressure on theassembly. In one embodiment a pneumatic press is used to exert positivepressure on the assembly. The construct is then dried optionally whilethe construct is under vacuum pressure. In one embodiment the meshcomprises a bioabsorbable material selected from the group consisting ofpolylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL),polydioxanone (PDO), trimethylene carbonate (TMC), polyvinyl alcohol(PVA), copolymers thereof, and blends thereof.

The collagen-based matrices (including the naturally occurringextracellular matrices) of the multiple layers composite prosthesisdescribed in the present invention can be further modified tobiochemically reinforce the collagen matrix. This includes the optionalmodification of one or more of the collagen-based matrices that comprisethe calcified/calcifying inducing layer, the scaffold layer and theextender layer.

In accordance with one embodiment the extracellular matrices of thecomposite construct are exposed to one or more compounds that modify thestructural components of the matrix to enhance the strength of thematerial. For example, in one embodiment, the collagen-based bioscaffoldis reinforced with glycine. For example in one embodiment thecollagen-based matrices are mixed with glycine at a concentration ofabout 0.01-0.3% wt. of the matrix material. In another embodiment thematrix material is intestinal tissue and the material is mixed withglycine at a concentration of about 0.1-0.3% wt. of the matrix material.This treatment is believed to block lysine-derived aldehydes fromforming during fibrilogenesis and may increase the diameter of thecollagen fibrils during enthesis regeneration.

In another embodiment the collagen based matrices are biochemicallyreinforced through the use of proteoglycans (PGs). Biochemicalreinforcement of collagen based matrices with proteoglycans (PGs) isachieved by contacting the collagen-based matrices with one or more PGsat a concentration of about 0.01-0.1% wt of the matrix material). PGsfunction to promote cross linking of collagen during remodeling and thusenhance the strength of the tissue during enthesis regeneration.

In another embodiment the collagen based matrices are mixed with MgSO₄and KH₂PO₄. As PGs are important in cross linking of collagens, theaddition of MgSO₄ and KH₂PO₄ is anticipated to assist in the synthesisof PGs and thus lead to reinforcement of the matrix after implantationinto a patient. In accordance with another embodiment the collagen basedmatrices are mixed with copper (II) sulfate pentahydrate (CuSO₄. 5H₂O)and/or Copper (II) chloride hydrate (CuCl₂.2H₂O). In one embodimentthese compounds are supplied at about 0.0002 to about 0.0006% ofnaturally occurring extracellular matrix or collagen based matrices. Cuis required for lysyl oxidase, which is involved in extracellular crosslinking of collagens during remodeling of naturally occurringextracellular matrices, such as intestinal submucosa. SO₄ ⁻² isanticipated to contribute to synthesis of new proteoglycans/GAGs.

In another embodiment the collagen based matrices are mixed with Fe⁺²,Mn⁺² and Ca⁺². Mixing collagen based matrices (including a naturallyoccurring extracellular matrix) with Fe^(|2) Mn^(|2) and/or Ca^(|2) mayenhance the post-translational modifications of collagen duringremodeling. Iron (Fe⁺²) is supplied, in accordance with one embodiment,at about 30 to about 60 mg/kg of the collagen based matrix byiron-dextran and/or iron (II) sulfate heptahydrate (FeSO₄. 7H₂O).Manganese (Mn⁺²) is supplied, in accordance with one embodiment, atabout 0.0003 to about 0.0009% of the collagen based matrix by manganese(II) sulfate monohydrate (MnSO₄, H₂O). In addition, in one embodiment,supplementing the collagen based matrices with Vit A, Vit B complex, VitC and Vit D is anticipated to have positive effects on collagenproduction during remodeling. It is believed that vitamin A plays a rolein cell differentiation and skeletal development, and vitamin D plays arole in cell growth, differentiation and bone mineralization. It is alsobelieved that all these vitamins play a role in collagen formationduring remodeling of collagen based matrices, including, for example,the remodeling of naturally occurring extracellular matrices. Thecollagen based matrices may also be supplemented with eicosapentaenoicacid. Supplementing the collagen based matrices with eicosapentaenoicacid is anticipated to have positive effect on tendon wound healing andcollagen production during remodeling.

The present invention also provides a method of attaching soft tissue toa metal implant. The method comprises the steps of providing a metalimplant construct, wherein the construct comprises: 1) a metal implantcomprising a porous region, wherein said porous region exhibits anano-textured surface and 2) a biocompatible polymer matrix coating thenano-textured surface, wherein the polymer matrix comprises a naturallyoccurring extracellular matrix with exogenously added biocompatibleinorganic materials distributed within the matrix. The biocompatiblepolymer matrix that coats the nano-textured surface is then contactedwith at least a portion of a scaffold layer, wherein the scaffold layercomprises a biocompatible polymer matrix and a biocompatible inorganicmaterial, and optionally, bioactive agents and exogenously added cellsand/or biologically derived agents. In one embodiment the scaffold layercomprises a naturally occurring extracellular matrix, such as intestinalsubmucosa. A portion of the scaffold layer is then attached to theproximal end of an extender portion, wherein the extender portioncomprises a naturally occurring extracellular matrix, and a syntheticportion coupled to the naturally occurring extracellular matrix. In oneembodiment the synthetic portion comprises a mesh member wherein saidmesh member is coated with comminuted submucosa-derived matrix. Uponimplantation into a patient, the distal end of the extender portion isattached to a patient's soft tissue.

In another embodiment, the extender comprises a naturally occurringextracellular matrix as a top tissue layer that is coupled to a bottomtissue layer of naturally occurring extracellular matrix, wherein thesynthetic portion is coupled to and positioned to lie between the toptissue layer and the bottom tissue layer. In a further embodiment theextender comprises multiple sections of a submucosal matrix, eachseparated by a synthetic portion and in one embodiment each section ofsubmucosal matrix includes multiple layers of submucosal matrix. In oneembodiment the submucosal matrix of the extender is intestinalsubmucosa. In one embodiment the synthetic portion comprises abiocompatible polymer. In one embodiment the synthetic portion comprisesa synthetic biocompatible polymer (for example a material selected fromthe group consisting of Prolene™, Vicryl™, and Mersilene™ andPanacryl™). In accordance with one embodiment, the synthetic portionincludes a mesh member coupled to at least one section of the naturallyoccurring extracellular matrix, and in one embodiment the mesh member isbioabsorbable. In another embodiment the mesh member further comprises alayer of comminuted, fluidized or gelled naturally occurringextracellular matrix coating the mesh.

The present invention also provides a kit for repairing a diarthrodialjoint, said kit comprising a metal implant construct, a scaffoldcomprising a biocompatible polymer matrix and a biocompatible inorganicmaterial and optionally bioactive agents and exogenously added cellsand/or biologically derived agents; and an extender graft comprising anaturally occurring extracellular matrix, and a synthetic portioncoupled to the naturally occurring extracellular matrix, said syntheticportion including a mesh member wherein said mesh member is optionallycoated with comminuted naturally occurring extracellular matrix. Moreparticularly, the metal implant construct comprises a metal implant thatincludes a porous region, wherein the porous region exhibits anano-textured surface, and a biocompatible polymer matrix coating thenano-textured surface. In one embodiment the biocompatible polymermatrix comprises intestinal submucosa with exogenously addedbiocompatible inorganic materials or bioactive agents distributed withinthe matrix. In another embodiment the biocompatible polymer matrixcomprises a synthetic biocompatible polymer coating coupled with abioactive agent. In yet another embodiment a biocompatible inorganicmaterial and/or bioactive agent is directly coupled to the nano-texturedsurface without a biocompatible polymer matrix. In one embodiment thebiocompatible inorganic material is hydroxyapatite, optionallyco-deposited with a bioactive agent, directly onto the nano-texturedsurface without a biocompatible polymer matrix. The kit can be used toimplant the metal prosthetic device in the patient and attach softtissues to the metal prosthesis by attaching the scaffold component tothe metal implant construct (in a manner that places the porous implantsurface with or without it's biocompatible polymer matrix coating indirect contact with the scaffold) and attaching one end of the extenderto the scaffold and attaching the other end of the extender to the softtissue of the patient.

The invention claimed is:
 1. A metallic implant to generate soft tissueand/or fibrocartilage tissue and/or bone on a metal surface to attachthe implant to a patient's tissues, said implant comprising: a metal orpolymer coating comprising nanosurfaced roughness produced fromanodization, one or more adhered nanoparticles, or etching of the metalsurface, the metallic implant further comprising an antibiotic compoundor an antimicrobial compound, where said implant is in contact with saidpatient's tissues.
 2. The implant of claim 1, wherein the polymercoating comprises a biocompatible polymer layer.
 3. The implant of claim1, wherein the implant has undergone hydrolysis.
 4. The implant of claim1, wherein the implant has undergone amidation.
 5. The implant of claim1, wherein the implant has undergone a gas plasma processing technique.6. The implant of claim 5, wherein the gas plasma processing techniqueis an ammonia plasma technique or an oxidative plasma technique.
 7. Theimplant of claim 1, wherein the anodization is performed by pretreatingthe metal surface of said implant with an acid; and anodizing saidpretreated metal surface at low voltage for at least 1 minute.
 8. Theimplant of claim 7, wherein the anodization is performed at low voltagefor 1 to 5 minutes.
 9. The implant of claim 8, wherein the metal surfacedisplaying the nanosurface roughness comprises titanium or a titaniumalloy, and wherein said pretreating step comprises immersing themetallic implant and a cathode in an acidic electrolyte solutioncomprising hydrofluoric acid; and said anodizing step comprises applyingan electrical potential between the metallic implant and the cathode.10. The implant of claim 9, wherein the electrical potential is about 20volts that is maintained for 1, 3 or 5 minutes.
 11. The implant of claim9, wherein the acidic electrolyte solution comprises 1% hydrofluoricacid.
 12. The implant of claim 9, wherein the acidic electrolytesolution comprises 1% hydrofluoric acid and 2% HNO₃.
 13. The implant ofclaim 1, wherein said metal surface displaying the nanosurface roughnesscomprises a plurality of surface structures having an average height offrom about 20 nm to about 200 nm.
 14. The implant of claim 13, whereinsaid surface structures have an average height of from about 20 nm toabout 100 nm.
 15. The implant of claim 13, wherein the distance betweensaid surface structures ranges from about 25 nm to about 500 nm.
 16. Theimplant of claim 1, wherein said implant further comprises a calcifiedmaterial layer coating the metal surface displaying the nanosurfaceroughness.
 17. The implant of claim 16, wherein the calcified materiallayer comprises hydroxyapatite.